Changing php.ini settings

Set a variable

Set the variable on your service. The new value applies when the container starts, with no rebuild:

services:
  php:
    image: serversideup/php:8.5-fpm-nginx
    ports:
      - 80:8080
    environment:
      PHP_MEMORY_LIMIT: "512M"
      PHP_POST_MAX_SIZE: "500M"
      PHP_UPLOAD_MAX_FILE_SIZE: "500M"
      PHP_DATE_TIMEZONE: "America/New_York"
    volumes:
      - .:/var/www/html

docker run --rm \
  -p 80:8080 \
  -v "$(pwd):/var/www/html" \
  -e PHP_MEMORY_LIMIT=512M \
  -e PHP_DATE_TIMEZONE=America/New_York \
  serversideup/php:8.5-fpm-nginx

Every variable and its default is in the environment variable specification.

Add your own ini file

PHP reads every .ini file in /usr/local/etc/php/conf.d/ in alphabetical order, and a later file overrides an earlier one. The image's settings are in serversideup-docker-php.ini, so name your file so it sorts after that, for example zzz-custom-php.ini:

FROM serversideup/php:8.5-fpm-nginx

COPY zzz-custom-php.ini /usr/local/etc/php/conf.d/

A setting in your file wins over the matching environment variable. If you set memory_limit in your file, PHP_MEMORY_LIMIT no longer changes it.

To replace the image's settings entirely, remove the default file as root. The PHP_* variables for php.ini settings, such as PHP_MEMORY_LIMIT and PHP_DATE_TIMEZONE, stop working once it is gone, because that file is where they are read. The PHP_FPM_* variables are read from the PHP-FPM pool configuration and keep working.

FROM serversideup/php:8.5-fpm-nginx

USER root
RUN rm /usr/local/etc/php/conf.d/serversideup-docker-php.ini
USER www-data

COPY zzz-custom-php.ini /usr/local/etc/php/conf.d/

Check the result

Print the value PHP is using:

docker compose exec php php -i | grep memory_limit

php -i shows the CLI's settings, which come from the same files. To see what the web server uses, open a page that calls phpinfo().